1. Field of the Invention
The present invention relates to vacuum fans used in the agricultural field, and, more particularly, to diffusers for such fans.
2. Description of the Related Art
The vacuum fan has a key roll in the apparatus used for planting seeds in a field. Among other possible functions, it is used to create a vacuum within a series of seed metering devices to pull seeds onto a metering disk so that they may be accurately and consistently delivered through the planter mechanism to the soil. The fan for this purpose typically has a high flow rate owing to the number of planter components. In the arrangement of the planter, the fan is placed behind the operator of a tractor used to pull or support the planting apparatus. The inlet or suction side of the fan is connected to the seed metering mechanisms but the outlet of typical vacuum fans is directed upward. The rotational speeds in the 3,000 to 5,000 RPM range necessary to produce the volume flow cause higher levels of noise in various frequencies. These can cause operator discomfort. Furthermore, the unaltered exhaust flow from the vacuum fan has a high velocity which creates turbulence and can effect the dust normally generated around the planting apparatus. This becomes essentially a greater problem if the outlet of the vacuum fan is pointed in a direction other than vertical when it is necessary to diffuse the exhaust air over the ground.
Accordingly, what is needed in the art is a vacuum fan exhaust that has velocity reducing and sound attenuating properties.